Red de instrumentacion y observatorio sismico de la universidad javeriana cali – rioja. nombre abreviado: resdi.

The threat of an earthquake is enough to require a careful consideration in the design of structures to defend property as the basic step to save human life. a seismic design involves the concept of earthquake-resistant specifications to assure the facilities will resist shaking without excessive damage. The identification of the parameter involved in the design of ground motion shakes is one of the most difficult task and, indeed, one of the most difficult problems faced by the geotechnical engineering or soil dynamics. The difficulties in designing structures arise from incomplete or uncertain information about the magnitude and location of a future event and more, from the effects a seismic ground motion can cause in a specific area. a designer may consider acceptable certain levels of damage or present a model providing greater earthquake resistance. In both cases, seismic analysis involves the quantitative estimation in costs and shaking hazard at a particular location. Different types of variables and earthquake sources of seismic activity must be identified and their potential for generating strong ground motions. Geological evidence, fault activity, magnitude indicators, tectonic evidence, past seismicity and data from instrumental recordings are important to identify and to evaluate the seismic hazard in a scenario. Deterministic processes are considered when a particular earthquake scenario is assumed, meanwhile probabilistic processes have been used in case uncertainties in size, location or time of occurrence are explicitly considered. In this investigation seismic hazard for micro-zones and particular sites with narrow boundaries will be addressed and studied, prevailing the concept of deterministic evaluation and comparing this whit the results from a probabilistic point of analysis. Deterministic methods characterize earthquake sources that produce significant ground motion at a site and geological and tectonic information is intended to be provided on the likelihood of occurrence of the controlling earthquake. Comparison with probabilistic hazard analysis in which uncertainties can be identified, quantified and combined, will provide a more complete picture of the seismic hazard. Deterministic processes will be computed in a tool to define the hazard in small zones relatively close to active faults. BEHAVIOR OF VERTICALLY PROPAGATING SEISMIC WAVES IN HORIZONTALLY LAYERED DEPOSITS Many methods have been proposed to study stress waves in elastic medium, ranging from experimental determination to direct integration of the equations of motion. Some procedure involving layered soils use a lumped mass approach of linearly elastic varying properties. Dynamic analysis of complex non-linear structural systems performed using step-by-step integration procedures are used in a bilinear solution regarding the stress-strain relationships are not linearly elastic. The equivalent linear approach is approximated to a bilinear system and the analysis of ground vibration can be carried out, so the shear modulus and damping are compatible with the strain induced in all layers. The problem will be extended to two dimensions using the concepts of the bilinear stress-strain bilinear model and the discrete equation of motion approach. Computed time histories of acceleration, relative velocity and relative displacements as long as shear strain and stress will be obtained at ground surface.